The multidisciplinary pediatric oncology program at UCLA will participate in the clinical research programs of the Children's Cancer Study Group (CCSG). This will allow UCLA physicians and patients to take part in clinical oncology studies which could not be undertaken in a single institution. UCLA has a program which focuses on certain pediatric neoplasms which have not benefitted from the recent advances in the oncologic armamentarium: a)recurrent acute lymphoblastic leukemia, b) acute myeloblastic leukemia, c) neuroblastoma, and d) histiocytosis-X. UCLA will participate in the development of new investigative programs dealing with the biology, diagnosis, and treatment of these neoplasms with CCSG. These programs will make use of the extensive experience of the UCLA team in the areas of bone marrow transplantation and tumor immunology. In addition, UCLA will initiate local pilot studies relevant to basic and applied pediatric oncology. The data generated by these studies will aid in the development of future limited-institution and Group-wide clinical studies.